Gas diffusion devices have long been used to control the distribution of gas in processes which require aeration treatment. In such processes, the gas diffusion device is located below the liquid surface and is connected to a source of gas supply.
One type of gas diffusion device known in the art is constructed of a porous medium. Numerous small openings in the porous medium break the gas into small bubbles thereby increasing the gas/liquid contact. A drawback of these prior art devices is that the porous medium has a tendency to clog thereby reducing or completely stopping the aeration process.
Another type of gas diffusion device known in the art is the hollow-bodied diffuser such as that shown in U.S. Pat. No. 3,679,187 to Smith. The Smith diffuser is a four-sided pyramid-shaped body which is submerged beneath a liquid surface and connected to a source of air supply. Four slot-shaped orifices release gas at four positions spaced 90.degree. apart on a vertical tube connected to a gas supply. The four-sided pyramid-shaped body is located directly above the slot-shaped orifices and is square in cross-section, having inclined planar surfaces positioned to spread out the air flow from the orifices. The gas is released through the orifices, rises to the flat inclined surfaces, and, because the surfaces are flat, does not become properly distributed before it reaches the shear edge, the edge of the pyramid-shaped body. The Smith diffuser does not sufficiently distribute gas because of the square cross-section and planar distribution surfaces. Thus, a need has arisen for a gas diffuser which is constructed to enable the efficient diffusion of gas into a liquid.